Roadmap

go-ruby-prime/prime is grown test-first, each capability differential-tested against MRI rather than built in isolation. Ruby's Prime — the deterministic, interpreter-independent number-theory core extracted from rbgo's internals — is complete.

Stage	What	Status
The generator	Take(n) / First(n) return the first n primes (Prime.take / Prime.first); Each(ubound, yield) enumerates every prime p <= ubound; EachPrime() is the unbounded cursor.	Done
Primality — exact	IsPrime(n) mirrors Prime.prime? / Integer#prime? exactly: numbers < 2 are not prime, every Carmichael number and strong pseudoprime is rejected. Trial division for small inputs, deterministic Baillie–PSW beyond, exact across the whole 64-bit range.	Done
Factorisation	PrimeDivision(n) returns [[p, exp], …] in ascending prime order (Prime.prime_division / Integer#prime_division), with a leading [-1, 1] for negatives and a ZeroError panic for 0. Large cofactors fall back to Pollard's rho.	Done
Reconstruction	Int(pairs) multiplies prime**exp back to the integer (Prime.int_from_prime_division), the inverse of PrimeDivision.	Done
Cursor	Next(n) / Prev(n) step to the adjacent prime.	Done
Differential oracle & coverage	Deterministic golden tables plus a differential oracle: a corpus computed both here and by the system ruby (Prime.prime?, Prime.take, Prime.prime_division, …) and compared; 100% coverage, gofmt + go vet clean, green across all six 64-bit Go arches.	Done

Documented out-of-scope boundaries

These are deliberate, recorded so the module's surface is unambiguous:

• No interpreter. The library implements the deterministic algorithm; it never runs arbitrary Ruby. Binding it to Ruby objects (the Prime.each enumerator, Integer#prime?) is the consumer's job — that is why rbgo binds this module rather than the reverse.
• Reference is reference Ruby (MRI). Byte-for-byte conformance on the integer value model targets MRI's Prime behaviour; differences across MRI releases are matched to the reference used by the differential oracle.
• Standalone & reusable. The module has no dependency on the Ruby runtime; the dependency runs the other way.

See Usage & API for the surface and Why pure Go for the deterministic/interpreter split.